HOW TO: Add Exisiting Free Space to Fedora 16 File System

I am totally new to Fedora (and Linux). I installed Fedora 16 from a DVD on my HP Laptop. Its a dual boot configuration with Windows-8. The installation was seamless, and I am able to boot into the OS of my choice. The problem for which I need the solution is as follows:

The windows portion uses abot 150+ GB of my 250 GB hard-disk (I am able to see it properly from the Windows Explorer). The remaining 80+ GB or so is for Linux. However from the File Manager application in Fedora shows only about 10 GB in use. What happened to the other 70 GB? While installing I created the root, boot (250MB), swap (6000MB) and home partitions as standard partitions.

IS THERE ANYWAY THAT I CAN GET BACK THAT 70 GB OR SO FOR USE IN FEDORA 16?
IS THIS REALLY A PROBLEM, BECAUSE MY CONCERN IS WHAT IF I RUN OUT OF THE ALLOCATED SPACE, WHEN THERE EXISTS AMPLE UNALLOCATED FREE SPACE IN THE DISK?
IS THERE ANYWAY THAT I CAN VISUALLY SEE HOW MUCH SPACE IS ACTUALLY ALLOCATED?
DISK USAGE ANALYSER SHOWS ONLY THAT I HAVE ALLOCATED DURING INSTALLATION.

This is what fdisk says:
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[root@localhost ~]# fdisk /dev/sda

Command (m for help): p

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8f8db8c2

Device Boot Start End Blocks Id System
/dev/sda1 * 63 305440742 152720340 7 HPFS/NTFS/exFAT
/dev/sda2 305440768 306464767 512000 83 Linux
/dev/sda3 306464768 318752767 6144000 82 Linux swap / Solaris
/dev/sda4 318752768 488396799 84822016 5 Extended
/dev/sda5 318756864 339236863 10240000 83 Linux
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